Children's ride-on vehicles are reduced-scale vehicles that are designed and sized for use by children. For example, children's ride-on vehicles include a seat adapted to accommodate one or more children as well as steering and drive assemblies that are adapted to be operated by a child sitting on the seat. One type of drive assembly that is often used in children's ride-on vehicles includes a battery-powered motor assembly that is adapted to drive the rotation of one or more of the vehicle's wheels. The motor assembly is powered by a battery assembly, which may include one or more rechargeable batteries. Typically, the vehicle will include an actuator, such as a foot pedal, push button or other user input device, which enables a child to select when power is delivered to the motor assembly. Some drive assemblies further include other user input devices, such as a speed selector and/or a direction selector, which are operated by a child sitting on the vehicle's seat to select the speed and/or direction in which the vehicle travels.
Children's ride-on vehicles are subject to being driven on a variety of surfaces, including concrete, dirt, and grass, as well as up and down hills. As a result, the power requirements for ride-on vehicles vary dramatically during operation. In particular, when driving on level or downhill hard surfaces, the motor may draw relatively little current, such as 2-5 amps. However, when traveling uphill or over rough surfaces like grass and dirt, substantially more current may be drawn, such as 35-40 amps sustained current. Similarly, when a child instantaneously starts the vehicle at full speed, such as by quickly pressing the foot-pedal from an unactuated position to a fully actuated position, a relatively high instantaneous current may be drawn from the battery. Thus, the batteries may be designed to be capable of delivering sufficiently high current levels for satisfactory operation under foreseeable operating conditions. The electrical drive systems of children's ride-on vehicles typically have some sort of current limiting device, such as a fuse or circuit breaker associated with the vehicle's battery assembly or electrically connected between the vehicle's battery assembly and its motor(s). The protection offered by these current limiting devices is necessarily limited by the operational current requirements of the motor(s) and/or other components of the vehicle's drive assembly.
Although a relatively high-current battery may be desirable for adequate vehicle performance, care should be taken when charging such a battery to avoid short circuits or other malfunctions in the battery charging circuit that could result in the battery delivering current, and especially high current, back into the battery charging circuit. The potential for such backflow current makes it desirable to provide protection within the charging circuit to protect against short circuits or other damage to the charging assembly.
A typical battery charging assembly for a battery-powered children's ride-on vehicle comprises a wall-mounted adapter, which contains a transformer and rectifier, a charger cord, and some sort of charging plug, probe or other connector that is adapted to electrically interconnect with the rechargeable battery of the ride-on vehicle. Such an adapter conventionally may include a circuit breaker that is designed to protect against excessive current draw from the AC wall outlet. However, it would be desirable to additionally offer protection against backflow current from the battery into the charging circuit.